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Now that she's lost 50 pounds, Jordin Sparks is looking -- and feeling! -- better than ever.

To celebrate her body makeover, the 22-year-old "Sparkle" actress posed in a sexy, blue bikini for the cover of Shape magazine's August issue.

PHOTOS: American Idol stars' weight woes

"I just wanted to be healthy," she says of her slim down. "I remember thinking, 'I'm in my prime. I should be happy and fit.' That was the moment I decided that changes needed to be made."

Making those dreams a reality was no easy feat for the Season 6 "American Idol" champ. "I knew I had a long road ahead of me. I was barely working out and my diet was a mess," Sparks says. "I had to address when, what and how much I was eating."

VIDEO: Jordin Sparks surprises a fan with an at-home visit

Several months in, Sparks noticed a change in her body. "The weight really started falling off and I could see my muscles," she tells Shape. "It was awesome!"

PHOTOS: The hottest bodies in Hollywood

The "Battlefield" singer's new film, "Sparkle" -- co-starring the late Whitney Houston -- is in theaters August 17.

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